Noise regulations in a key Latin American country were revised to a lower level, forcing CNH and other construction equipment manufacturers to reduce the noise footprint of their products. The new specification uses a formula to determine the allowable sound pressure level based on the power of the machine. In this case, the new standard required a noise reduction of about 6 dB(A) relative to the existing design. The noise measurements are based on the ISO 6393 standard. Six microphones are arranged in a hemisphere at specified locations around the equipment and the sound pressure level is measured while the equipment is operated under high idle conditions. CNH engineers ran physical tests in an effort to better understand the noise contributors. Among any things, they turned the fan on and off, turned the hydraulic pump on and off, and masked the sound coming from the exhaust to better understand the relative importance of the noise contributors. The analysis showed that the fan was the number one contributor.